Grant is detailed by his city editor to interview Major Russelle, just returned from Panama, about an attempt made by foreign spies to steal from him the plans of the canal's fortifications. The spies ingratiate themselves into the favor of the Major's wife and tempt her with a gorgeous necklace which she desires but is unable to pay for. When Grant calls for his interview he has an opportunity to see which way the wind is blowing, and the next day when he sees the Major's wife descend in the hotel elevator and learns from the clerk that she has visited the spies' apartments, his suspicions are aroused. He returns to the Major's home and insists that the Major open his private safe to see if the plans are still there. They are missing. Calling a taxi, Grant rushes to the dock in time to see the boat well on its way down the harbor. Jumping into a gasoline launch he gives chase and as the speedy little craft runs alongside the giant liner he makes a leap for the rope ladder that has been lowered, boards the ship and finds the portfolio of plans hidden in the spies' stateroom. Leaping into the sea he is picked up by the motor boat and returns in time to save Major Russelle's wife from harming herself in remorse over having betrayed her husband's honor.